491
FXUS65 KBYZ 092059
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
259 PM MDT THU JUL 9 2026
KEY MESSAGES
- EXTREME HEAT EXPECTED THIS WEEKEND. HIGH TEMPERATURES EXCEEDING
100 DEGREES WITH OVERNIGHT LOW TEMPERATURES IN THE 60S AND 70S
WILL PRODUCE CUMULATIVE HEAT STRESS.
- HIGH TEMPERATURES ON SUNDAY MAY CHALLENGE ALL-TIME RECORDS AT
ALL CLIMATE SITES.
- ISOLATED SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND FAR
SOUTH-EASTERN MONTANA THIS AFTERNOON AND EVENING.
- SLIGHT CHANCE OF SHOWERS, AND MAYBE A FEW WEAK THUNDERSTORMS,
FRIDAY AFTERNOON AND EVENING.
DISCUSSION
TODAY THROUGH WEDNESDAY...
ISOLATED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE
BIGHORN MOUNTAINS THIS AFTERNOON AS A SUBTLE SHORTWAVE TROUGH
MOVES THROUGH THE ZONAL FLOW ALOFT. WITH THIS, ADDITIONAL ISOLATED
SHOWERS AND THUNDERSTORMS ARE POSSIBLE INTO THE EARLY EVENING
OVER THE BIGHORN MOUNTAINS, AS WELL AS THE ABSAROKA-BEARTOOTH
MOUNTAINS. WHILE THE CHANCE IS LOW, A FEW THUNDERSTORMS MAY ALSO
DEVELOP OVER CARTER COUNTY IN FAR SOUTH-EASTERN MONTANA THIS
AFTERNOON AND EARLY EVENING. WITH THIS, A STRONG THUNDERSTORM IS
POSSIBLE (LOW RISK), THOUGH THE BEST THUNDERSTORM INGREDIENTS
CURRENTLY EXIST OVER SOUTH DAKOTA.
AS RIDGING BUILDS INTO THE REGION FRIDAY, TEMPERATURES WILL WARM
INTO THE UPPER 80S AND 90S FOR MANY LOCATIONS. WHILE DRY
CONDITIONS WILL PREVAIL THROUGH MUCH OF THE DAY, SOME WEAK ENERGY
MOVING IN FROM THE SOUTHWEST MAY BE ENOUGH TO GENERATE HIGH- BASED
SHOWERS AND WEAK THUNDERSTORMS DURING THE AFTERNOON AND EVENING
(15 PERCENT CHANCE). WITH THIS, GUSTY AND ERRATIC WINDS MAY
DEVELOP WITH DRY AIR IN PLACE NEAR THE SURFACE.
SATURDAY THROUGH MONDAY, THERE CONTINUES TO BE HIGH CONFIDENCE IN
THE FIRST WIDESPREAD SIGNIFICANT HEAT WAVE OF THE SUMMER AS A
STRONG UPPER LEVEL RIDGE BUILDS INTO THE REGION. CURRENTLY,
FORECAST HIGH TEMPERATURES OF 95 TO 110 DEGREES ARE FORECAST,
WARMEST ON SUNDAY, WITH LOCAL MAXIMA ABOVE 110 DEGREES POSSIBLE
OVER THE PLAINS (MODERATE CHANCE). TEMPERATURES THIS WARM WILL
THREATEN ALL- TIME RECORD HIGH TEMPERATURES AT ALL CLIMATE SITES
ON SUNDAY (SEE TABLE BELOW FOR ALL- TIME RECORD HIGH
TEMPERATURES). TEMPERATURES THIS WARM ARE SUPPORTED BY THE VERY
WARM TEMPERATURES ALOFT THAT ARE MODELED DURING THIS TIME (700MB
TEMPERATURES NEAR OR EXCEEDING 20C). ALONG WITH THE SIGNIFICANT
DAYTIME TEMPERATURES, OVERNIGHT LOW TEMPERATURES IN THE 60S AND
70S, WARMEST SUNDAY NIGHT, WILL EXACERBATE THE RISK OF HEAT
STRESS. THEREFORE, THE EXTREME HEAT WATCH IS NOW IN EFFECT FROM
SATURDAY MORNING THROUGH MONDAY EVENING.
ALONG WITH THE HEAT, VERY DRY CONDITIONS WILL EXIST, WITH
RELATIVE HUMIDITY VALUES DECREASING INTO THE SINGLE DIGITS TO
TEENS PERCENT SATURDAY AND SUNDAY, AND TEENS TO 20S PERCENT
MONDAY. ON SUNDAY, A WIND SIGNAL HAS STARTED TO APPEAR IN THE
MODELS. CURRENTLY, PEAK WIND GUSTS IN THE 20S AND 30S MPH ARE
FORECAST SUNDAY INTO SUNDAY NIGHT. THE COMBINATION OF BREEZY
WINDS, VERY HOT TEMPERATURES, AND VERY DRY CONDITIONS WILL
INCREASE THE RISK OF FIRE WEATHER CONDITIONS. TAKE CARE NOT TO
CAUSE A SPARK AND FOLLOW LOCAL BURN REGULATIONS.
HEADING INTO THE FIRST HALF OF NEXT WEEK, ENSEMBLES SUGGEST THE
UPPER LEVEL RIDGE WILL DECREASE IN STRENGTH A BIT, ALLOWING
SLIGHTLY "COOLER" TEMPERATURES TO RETURN TO THE FORECAST (UPPER
80S AND 90S). MONSOONAL MOISTURE ALSO LOOKS TO LIFT FROM THE
SOUTHWEST INTO NORTHERN WYOMING AND SOUTHERN MONTANA, BRINGING AT
LEAST AN OCCASIONAL SLIGHT CHANCE OF PRECIPITATION BACK TO THE
FORECAST. WITH THIS, HIGH BASED SHOWERS AND THUNDERSTORMS WOULD BE
FAVORED, MEANING THE MAIN THREAT IS GUSTY AND ERRATIC WINDS.
BELOW ARE THE ALL-TIME RECORD HIGH TEMPERATURES AT EACH OF OUR
CLIMATE STATIONS:
BILLINGS, MT 108F
LIVINGSTON, MT 105F
MILES CITY, MT 111F
SHERIDAN, WY 107F
BAKER, MT 109F
AVIATION
ISOLATED SHOWERS ARE POSSIBLE THIS AFTERNOON OVER THE MOUNTAINS
OF SOUTHERN MONTANA AND NORTHERN WYOMING. A WEAK THUNDERSTORM OR
TWO IS ALSO POSSIBLE, WITH KSHR BEING THE MOST LIKELY (15%)
TERMINAL TO BE IMPACTED BY ANY SHOWERS OR STORMS. OTHERWISE, LOOK
FOR VFR CONDITIONS TO PREVAIL THROUGH THE PERIOD. MATOS
PRELIMINARY POINT TEMP/POPS
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 062/097 065/104 068/109 072/098 070/095 068/094 066/090
01/U 10/G 00/G 00/U 10/U 23/T 51/U
LVM 054/094 056/101 060/105 062/096 061/094 059/092 057/089
02/T 20/G 00/G 00/U 12/T 45/T 42/T
HDN 059/097 063/104 065/110 070/099 069/096 067/094 065/092
01/U 10/G 00/G 00/U 11/U 32/T 41/U
MLS 060/099 067/105 069/110 074/100 069/096 068/095 067/092
00/U 10/G 00/G 00/U 10/U 22/W 41/U
4BQ 060/097 067/104 068/108 076/100 069/097 069/095 068/092
01/U 10/G 00/G 00/U 00/U 22/T 41/U
BHK 057/094 065/102 067/107 072/099 065/094 064/094 064/091
00/U 01/G 00/G 00/U 00/U 22/T 31/U
SHR 055/094 059/101 062/107 068/098 064/096 064/093 062/090
02/T 10/G 00/N 00/U 01/U 14/T 33/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...EXTREME HEAT WATCH IN EFFECT FROM SATURDAY MORNING THROUGH
MONDAY EVENING FOR ZONES
29>34-36-37-40-42-56>58-63>66-138-139-141-169-170-172-173-228-235.
WY...EXTREME HEAT WATCH IN EFFECT FROM SATURDAY MORNING THROUGH
MONDAY EVENING FOR ZONE 199.
WEATHER.GOV/BILLINGS
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